Common mistakes in a recipe

This page should list common (!) mistakes when defining a recipe. a link or one sentence explaining what the problem is are a bonus. But keep it short!

(R)DEPENDS, etc.

libiconv in (R)DEPENDS

Use "virtual/libiconv" instead as glibc based systems already have libiconv functionality from glibc. Uclibc based systems will get it from "libiconv". By building libiconv in glibc build You risk a corrupted TMPDIR which will need to be restarted from scratch.

kernel modules in RDEPENDS

Never use RDEPENDS to drag kernel modules into an image, use RRECOMMENDS instead. The reason is that some devices can have those modules built-in into kernel.